Interlocking electric switch



26 1927. July w. B. BURKE ET AL v INTERLOCKING ELEQTRIC SWITCH Filed July By 1923 I N VEN T0115 UZZZ ZU 1331/?5 and B Eawaw ZJe 126 r the annexed drawin and the b mechanism embodying Patented July 26, 1927.

UNITED STATES PATENT OFFIC "WILBUR B. BURKE AND EDWARD G. WEILER, 0F

WEILER ASSIGNOR TO SAID Application filed July 5,

. In various industrial operations where electric current of high voltage isemployed. it becomes desirable to prevent access to the apparatus through whichthe current is being passed or to the'room or chamber in which such apparatus is located while the current on. In other words, positive protection may be thus secured for the worle men about such apparatus and the liability to serious accidents greatly, if not entirely, reduced despite the employment of such high voltage current. y I

The object of thc present invention accordingly is the provision of a switch opcrating mechanism which will be controlled by the position of a door or equivalent closure which is adapted to prevent access to the apparatus in WlllCll't'he current is being used. 7 The control is so arranged that the switch cannot be closed and the current thus passed through the apparatus in question until the door is closed and vice versa the latter'cannot be opened until the switch has been opened and the flow of current through the apparatus thus broken.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, following forth in detail certain the invention, such however, but

description setting disclosed means constituting.

one of various mechanical forms in which the principle of the invention may beused.

In said annexed drawing Fig. l is an elevational view of a switch having associated therewith our improved safety control device; Fig. 2 is a transverse horizontal section of the foregoing on a somewhat larger scale, the plane of the section being indicated by the line 22, Fig. 1; Fig. 3 is a view, similar to that of Fig. 2, but showing the parts in a different operative position, and Fig. 4 is a vertical sectional View of a detail taken on a plane at right angles to that of Figs. 2 and 3, the plane of the section being indicated by the line M, Fig. l.

The switch 1 illustrated in the several Figures of the drawing is of the familiar knife type and is arranged to control the supply of current from leads 2 to a suitable apparatus (not shown). Such switch and other appurtenant parts as plunger 7, is one end of EAST CLEVELAND, 01110; snm

BURKE. 1

INTERLOCKING ELECTRIC SWITCH;

Serial No. 649,448.

panel board 3 which in the case in hand is set in the wall of a chamber or casing 4 in which is housed the apparatus to which the current is to be supplied. Access to the interior of such chamber or casing is had through a door 5 shown as hinged about pintles 6 in the door opening and capable being pivotally attached to the movable end of the switch 1, while the outer end of said plunger is provided witha handle 8 for its convenient operation. A compression spring 9, mounted as shown, may be employech'if desired, to assist in, the opening of the switch or to automatically effect such opening in 'somecases.

Pivotally connected withthe freeend of the switch'l, preferably about the same axis a bar link 10, the V other end of which is pivotally attached to a reciprocableplunger 11 that is adapted'to project through the adjacent side member 12 of the frame of door 5. Where such frame consists, as shownrof angle bars,the construction of the chamber or casingv l being preferably'of metal, a suitable guide 13 may be provided to assist in supporting said plunger 11. The length of the latter is such that when the switch 1 is closed, the end of the plunger will project through the frame member 12, while on the other hand when the" switch is open, it is withdrawn within said member or guidelil so as to leave the doorway entirely clear (see Figs. 2 and 3)." They edge of the door adjacent said frame member 12 is formed or provided with a transversely curved section 15 that as the door is swung from open to closed position and vice versa fits snugly against said frame member, the curve of such section having pintles 6 for its axis. Such door section 6 is provided with an aperture 16 or otherwise interrupted at one point only to permit the passage therethrough of plunger 11, such aperture being aligned with the plunger only when the door is fully closed. In other words, in any other position of the are mounted on a door such curved section 15 serves as an cffeetual ate for said plunger and absolutely prevents t e closure of the switch due to the toggle formation which the latter when open resents in conjunction with link 10. For t e purpose of lockin closed, a transversely sli able bolt 17 is provided on its inner side, such bolt carrying a knob 18 that rojects through a slot 19 in the door for t e purpose of external manipulation of the bolt. In its operative position the outer end of this bolt engages with a suitable aperture in the sidemember 12 of the door frame oppositethe previous- I mentioned side member 12 of such frame. guch bolt is aligned in the closed position of the door with the plunger 11, its inner end being adapted to be engaged byv the adjacent end. of said plunger when the latter projects through frame member 12 and aperture 16 in the curved stop on the door. A collar 20 on bolt 17 serves by engagement withthe adjacent portion ofthe door to'limit the retractivemovement of the bolt as will be readily understood. 3

As a result of the foregoing construct-ion when the door has been properly closed, not

only is the switch 1 free to be closed upon ulling outwardly on plunger 7, by reason of the, fact that such aperture 16 in stop 15 is aligned with plunger 11, but the move ment of the latter through such aperture serves to project the bolt 17 into locking enagement with frame member 12 so as to securely lock th door in such closed position. Conversely the bolt 17 cannot be retracted so as to permit the door to be opened until said lunger 11 has been moved out of the way y first opening the switch inthe man- .ner hereinbefore described. To assist in retaining theswiteh in closed'position against the tendency of spring 9 where the latter is employed, a pivotal latch 21, as shown .in Fig. 4, may be employed, such latch being arranged for engagement by link 10 when the latter is straightened out incidentally to closing switch 1. A pin 22 slidably mounted Hi the panel 3 is adapted to engage a downwardly extending arm 23 on the ,latch so; as to release link 10 when desired.

In addition .to or in place of such manually operable means for releasing the latch 21, an automatic device may be provided consisting ofa solenoid 25, the armature 26 of which is adapted upon energization ofsuch solenoid to strike a projection 27 .on the the door when.

the one explained, change latch arm 23 and thus raise the latch clear of the link 10. As sliown'in Fig. 1, the circuit 'for such solenoid may be controlled by a clock 28 or equivalent timing mechanism so that once'the door 5 is closed, it cannot again be opened until after a prescribed time has elapsed.

Other modes of applying the principle of our invention may be employed instead of eing made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

We therefore particularly point out and distinctly claim as our invent1on:-

1. In mechanism of the character described, the combination of an electric switch of the knife type, a pivotally hung door, a plunger adapted to project into the path of movement of said door, a link connecting said plunger with said switch, a stop on said door arranged to lie in the path of saidplunger except in closed position of said door, and a with said link to retain said switch closed and said plunger projected.

2. In mechanism of the character described, the combination of an electric switch of the knife type, a pivotally hung door, a plunger adapted to project into the path of movement of said door, a link con necting said plunger with said switch, a stop on said door arranged to lie in the path of said plunger except in closed position of said door, a latch adapted to engage with said link to retain said switch closed and said plunger projected, and manually operable means adapted to release said latch.

23. In mechanism of the character described, the combination of an electric switch of the knife type, a pivotally hung door, a plunger adapted to project'into the path of movement of said door, a link connecting said plunger with said switch, a stop .on said door arranged to lie in the path of said plunger except in closed position of said door, a latch adapted to engage with said link to retain said switch closed and said plunger projected, and time controlled means adapted to release said latch.

Signed by us, this 2d day of July, 1923.

WILBUR B. BURKE. EDWARD G. WEILER.

latch adapted to engage 

